Sekiya and Morimoto, Chem. Pharm. Bull., 23, 2353 (1975) disclose that the reaction of trichloroacetic anhydride with Schiff bases yields 3,3-dichloro-2-azetidinones.
U.S. Pat. No. 4,064,120, issued Dec. 20, 1977 discloses antiinflammatory compounds having the formula ##STR3## wherein the symbols are as defined above under the heading "Related Application".